roImageCanvas Image Cancellation

Assuming a call to ClearLayer doesn't cancel the transfer, you could potentially use the AsyncGetToFile method of the roUrlTransfer component to download it to a tmp: location prior to setting the layer on the image canvas. Since it won't display until it's fully downloaded anyway, it shouldn't incur any additional performance penalties, and gives you the ability to cancel the transfer without having to recreate the canvas.

Thanks! I hadn't thought about clearlayer. How would you cancel a file transfer in progress? I see your answer to copy the file to tmp, and then display it if it 'hasn't been cancelled' by the user, but the file that way would still be transferred taking up the bandwidth to get the whole file. I'd like to cancel it partway, before it's done transferring - if it's possible. If not, that's ok - just not preferred.

"destruk" wrote:
Thanks! I hadn't thought about clearlayer. How would you cancel a file transfer in progress? I see your answer to copy the file to tmp, and then display it if it 'hasn't been cancelled' by the user, but the file that way would still be transferred taking up the bandwidth to get the whole file. I'd like to cancel it partway, before it's done transferring - if it's possible. If not, that's ok - just not preferred.

If you use AsyncGetToFile, you can call AsyncCancel to cancel the transfer. Oddly enough, I don't see AsyncCancel documented in the component reference, but you can see it in use in the urlUtils.brs file in the videoplayer example.

Thanks a bunch! This is great!

and thanks for pointing out the doc bug. I'll remedy that in the next SDK release.

--Kevin